Receiver and Wireless Power Supply System

This application is a Continuation-in-Part of International Application No. PCT/JP2024/006421, filed on Feb. 22, 2024, which claims the benefit of priority to Japanese Patent Application No. 2023-063317, filed on Apr. 10, 2023, the entire contents of both of these applications are hereby incorporated by reference.

The present disclosure relates to a receiver and a wireless power supply system.

There is a technology related to a charging device including: a power acquisition unit that charges a first power storage unit with a voltage supplied from outside; and a power transfer unit that transfers the electric power stored in the first power storage unit to a second power storage unit having a larger capacity than the first power storage unit and stores the electric power, wherein the power transfer unit includes a voltage drop suppression unit that suppresses a voltage drop per time in the first power storage unit when the electric power is transferred from the first power storage unit to the second power storage unit (Patent Document 1).

Patent Literature 1 JP 2016-226130

A wireless power supply system is known that uses microwaves to supply substantially continuous power from a transmitter to a receiver. In such a wireless power supply system, there is a need to quickly secure an operation voltage of a control circuit for controlling a receiver at the beginning of wireless power supply from the transmitter, while there is also a need to continue stable operation of the receiver even if the wireless power supply from the transmitter is interrupted.

1 However, the technique disclosed in Referencerelates to an electronic device to which operating power is supplied from outside by RFID technology. Therefore, since the operating power supplied from the external device in Patent Document 1 is not continuous, it is difficult to cope with the above-described needs.

An object of the present disclosure is to provide a technique that achieves both prompt operation of the receiver and stable continuation of operation in the receiver to which wireless power is supplied.

A receiver wirelessly receives transmitting power composed of AC signals, wherein the receiver includes a rectifying unit for rectifying transmitting power, a power management unit for managing a rectified voltage from the rectifying unit, a charging unit that is charged with an output voltage from the power management unit, and a control unit that operates with supply power from the charging unit and controls the entire receiver, wherein the charging unit includes a plurality of capacitors, and performs charging of one of the plurality of capacitors until a predetermined time from the start of receiving the transmitting power, and charges capacitors other than the one capacitor after the predetermined time.

According to the present disclosure, it is possible to provide a technique that achieves both prompt operation of a receiver and stable continuation of operation in a receiver to which wireless power is supplied.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In all the drawings describing the embodiments, the same components are denoted by the same reference numerals, and repeated description thereof is omitted. Note that the following embodiments do not unduly limit the contents of the present disclosure described in the claims. In addition, not all of the constituent elements shown in the embodiments are necessarily essential constituent elements of the present disclosure. In addition, the drawings are schematic diagrams, and are not necessarily strictly illustrated.

In the following description, a “processor” is one or more processors. The at least one processor is typically a microprocessor such as CPU (Central Processing Unit), but may be other types of processors such as GPU (Graphics Processing Unit). The at least one processor may be single-core or multi-core.

Also, the at least one processor may be a processor in a broad sense, such as hardware circuitry (e.g., FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) that performs some or all of the processes.

Further, in the following explanation, information in which an output is obtained with respect to an input is sometimes described by expressions such as “xxx table”, but this information may be data of any structure or a learning model such as a neural network that generates an output with respect to an input. Therefore, the “xxx table” can be referred to as “xxx data”.

Further, in the following description, the configuration of each table is an example, and one table may be divided into two or more tables, or all or a part of two or more tables may be one table.

Further, in the following description, the processing is sometimes described using a “program” as a subject, but the program is executed by a processor, so that the defined processing is performed by appropriately using a storage unit, an interface unit, or the like, so that the subject of the processing may be a processor (or a device such as a controller having the processor).

The program may be installed in a device such as a computer, or may be in a program distribution server or a computer-readable (e.g., non-transitory) recording medium. In the following description, two or more programs may be implemented as one program, or one program may be implemented as two or more programs.

In the following description, an identification number is used as identification information of various objects, but identification information of a type other than the identification number (for example, an identifier including an alphabetic character or a code) may be adopted.

In addition, in the following description, when elements of the same kind are described without being distinguished, reference numerals (or common symbols among reference numerals) are used, and when elements of the same kind are distinguished and described, identification numbers (or reference numerals) of the elements may be used.

In the following description, the control lines and the information lines indicate those considered necessary for explanation, and not necessarily all control lines or information lines of an actual product are shown. All configurations may be interconnected.

WPT system according to the present disclosure includes a receiver that receives power transmitted from a transmitter and supplies the power to a device based on a wireless power supply method.

Although described in detail in the first embodiment, in the WPT system according to the present disclosure, microwave power (substantially continuous continuous wave (CW) of 920 MHz) is received by an antenna of a receiver, and a radio wave is converted into a DC voltage by a rectifier circuit functionally connected to the antenna. The DC voltage output from the rectifier circuit is supplied to the charging unit (mainly the capacitor) after the voltage is controlled by the power management unit.

There is no particular limitation on the power storage element that comprises the charging unit, and examples include a capacitor, a lithium-ion battery, an electrical double-layer capacitor, a ceramic capacitor, and the like. In WPT system according to the present disclosure, the charging unit will be described as mainly including a capacitor.

The voltage supplied from the power management unit is supplied to the charging unit when the voltage stored in the charging unit is less than a predetermined value. When the charging unit is charged up to a predetermined voltage, the electric power supplied from the electric power management unit is supplied to a microcontroller.

Here, the operating power of the microcontroller that performs overall control of the receiver in the wireless power supply depends on the microwave power received by the receiver. Further, in WPT system of the present disclosure, the charging unit is mainly provided with a capacitor, and therefore, at the beginning of the wireless power supply from the transmitter, an adequate voltage for operating the microcontroller is not accumulated in the charging unit. For this reason, it is desirable that a sufficient voltage is accumulated in the charging unit as early as possible from the start of wireless power supply from the transmitter, and the microcontroller is operated at an early stage.

In consideration of this viewpoint, it is preferable to reduce the capacitance (hereinafter, simply referred to as “capacity”) of the capacitor constituting the charging unit to rapidly charge the charging unit to accumulate a predetermined voltage in the capacitor.

On the other hand, in the wireless power supply, since the power supply condition depends on the environment, it is difficult to stably supply a constant amount of power, and the amount of power supply greatly fluctuates over time. In addition, the amount of power supply can also vary similarly in the wireless power supply of a solar cell or a laser system. Even in such a situation where the power supply condition is not stable, it is necessary to continue stable power supply to the microcontroller of the receiver and the sensor device of the receiver.

In consideration of this viewpoint, it is preferable to increase the capacitance of the capacitor constituting the charging unit so that stable power supply to the microcontroller and the like can be continued as much as possible even if a change occurs in the power supply condition.

As described above, regarding the capacitance of the capacitor constituting the charging unit in the WPT system of the present disclosure, there exist in a sense conflicting viewpoints as mentioned above, and these are in a trade-off relationship.

Therefore, in the WPT system according to the present disclosure, a plurality of capacitors are provided in the charging unit of the receiver, and charging of one of the plurality of capacitors is performed from the start of wireless power supply from the transmitter (the start of receiving of the transmitting power) up to a predetermined period of time, and charging is performed until the operation power of the microcontroller or the like can be secured. Then, after a predetermined period of time has elapsed, the capacitor other than one capacitor is also charged to increase the capacity of the entire charging unit to perform charging. Thus, stable power supply to the microcontroller or the like can be performed, and even if the power supply condition from the transmitter changes, the power supply to the microcontroller or the like can be stably continued.

In this case, it is preferable that the capacity of the one capacitor is equal to or smaller than that of the other capacitor (hereinafter, referred to as “another capacitor”). Accordingly, it is possible to charge the microcontroller or the like more quickly until the operation power can be secured during a predetermined time from the start of receiving the transmitting power, and as a result, it is possible to start the operation of the receiver more quickly. On the other hand, by making the capacitance of another capacitor equal to or larger than the capacitance of one capacitor, if another capacitor is sufficiently charged after a predetermined time has elapsed, the power supply to the microcontroller or the like can be more stably continued even if the power supply condition from the transmitter changes.

It should be understood that the specific configuration of the WPT system according to the present disclosure is not limited to the configuration described above.

1 FIG. 1 is a diagram showing an entire configuration of a WPT systemaccording to a first embodiment.

1 FIG. 1 FIG. 1 100 200 300 400 1 As shown in, the WPT systemincludes, for example, a transmitter, a receiver, a first information processing device, and a second information processing device. The WPT systemshown inis used, for example, in a building or a factory.

100 100 200 200 100 200 100 100 100 200 Note that in this specification, the transmitteris a (electric power) transmitterin the sense of transmitting power wirelessly, and similarly, the receiveris a (electric power) receiverin the sense of receiving power wirelessly. As described below, the transmittermay transmit, for example, information regarding the state of the receiveror information regarding the measurement results by a sensor as data signals to the transmitter, and the transmittermay receive such data signals. In this case, the transmitteris a receiver that receives a data signal, and the receiverfunctions as a transmitter that transmits a data signal.

1 FIG. 1 100 100 1 100 1 In, WPT systemincludes three transmitters, but the number of transmittersincluded in WPT systemis not limited to three transmitters. The number of transmittersincluded in WPT systemmay be two or less, or four or more.

1 FIG. 1 200 200 1 200 1 In, WPT systemincludes seven receivers, but the number of receiversincluded WPT systemis not limited to seven. The number of receiversincluded in WPT systemmay be six or less, or eight or more.

1 FIG. 1 300 300 1 300 1 In, WPT systemincludes two first information processing apparatus, but the number of first information processing devicesincluded in WPT systemis not limited to two. The number of the first information processing deviceincluded in WPT systemmay be one or three or more.

100 200 100 200 100 200 100 The transmittertransmits, for example, a power supply signal or a data signal to the receiver. The transmittertransmits a power supply signal to the receiverby, for example, a radio wave of a 920 MHz band. The transmittertransmits a data-signal to the receiverby, for example, a radio wave in a 2.4 GHz band. The transmittermay transmit the data-signal by radio waves in a 920 MHz band.

100 100 200 100 200 200 100 200 The transmission signal transmitted from the transmittermay be, for example, a continuous wave (CW) having a predetermined power. In addition, the frequency band of the power transmission signal is, for example, a 920 MHz band in consideration of the distance between the transmitterand the receiver. If the frequency band is higher than the exemplified frequency band, if the distance between the transmitterand the receiveris not shortened, there is a possibility that the receivercannot supply a predetermined power operable, and therefore an appropriate frequency band can be determined in consideration of a practical range (for example, the distance between the transmitterand the receiveris several meters).

1 100 100 In this case, WPT systemmay be installed in a state in which the power transmission signal is intermittently transmitted. As an example, when a transmission signal from the transmitterfalls under the provisions of a Radio wave station prescribed in the Radio Law of Japan (whether or not there is a license), it may be necessary to provide a fixed pause period for the transmission signal based on the Radio Law. In this case, the transmission signal cannot be said to be a continuous wave when considered on a certain time axis. However, since it is necessary to provide a pause period, and this pause period is sufficient if it is small, the transmission signal transmitted from the transmittercan be regarded as a substantially continuous wave. The method of setting the rest period itself can be arbitrarily selected. That is, if there are the above-mentioned legal restrictions or the like, an arbitrary pause period may be provided to the extent that this restriction or the like is complied with. Further, if it is necessary to provide a pause period in order to increase the temperature of the transmitter by continuously operating the transmitter, it is sufficient to provide an arbitrary pause period for keeping the temperature of the transmitter constant. The term “arbitrary” as used herein means that the time width of the pause period itself, the timing when the pause period is repeated (whether it is periodic or not may be based on legal restrictions, etc.) and the like can be arbitrarily set.

100 200 200 100 200 200 100 100 100 100 200 200 For example, the transmittermay supply power to one receiveror a plurality of receivers. For example, the transmittermay transmit a data signal to one receiveror may transmit a data signal to a plurality of receivers. The transmittermay transmit the same data signal as another transmitteror may transmit a different data signal than another transmitter, for example. For example, the transmittermay transmit a predetermined command signal as a data signal to the receiver, or may transmit a preset signal as a data signal to the receiver.

100 200 100 200 200 100 200 300 100 100 300 The transmitterreceives, for example, a data signal transmitted from the receiver. For example, the transmittermay receive data signals transmitted from one receiveror may receive data signals transmitted from a plurality of receivers. The transmittertransmits the data signal transmitted from the receiverto the first information processing device. The transmittertransmits information relating to the state of the transmitterto the first information processing device.

200 100 200 200 100 200 200 100 The receiverreceives, for example, a power supply signal and/or a data signal transmitted from the transmitter. For example, in a case where the receiverhas a charging unit, the receiverconverts the power supply signal transmitted from the transmitterinto converted electric power, and stores the converted power in the charging unit. For example, when the receiverhas a predetermined sensor, the receiverconverts the power supply signal transmitted from the transmitterinto power, and drives the sensor with the converted power.

200 200 100 The receivertransmits, for example, information regarding the state of the receiveror information regarding the measurement result by the sensor to the transmitteras a data signal.

300 100 200 1 300 100 200 100 200 100 300 400 The first information processing deviceis an information processing device that monitors the operation of the transmitterand the receiveraccommodated in the WPT system. For example, the first information processing devicedetermines whether or not the transmitteror the receiveris in a preset state, based on information relating to the state of the transmitterand the receivertransmitted from the transmitter. When it is determined to be in a preset state, the first information processing apparatustransmits predetermined information to the second information processing device.

300 100 200 1 300 100 200 100 300 Further, the first information processing devicestores information on the transmitterand the receiveraccommodated in the WPT system. For example, the first information processing devicestores information relating to the state of the transmitterand the receivertransmitted from the transmitterin a storage unit provided in the first information processing device.

300 100 1 Further, the first information processing devicecontrols the operation of the transmitteraccommodated in the WPT system.

400 1 400 300 100 200 1 400 100 200 The second information processing deviceis an information processing device operated by an administrator of the WPT system. When the second information processing devicereceives, from the first information processing device, a notification indicating that the transmitter, the receiver, or both of them accommodated in the WPT systemare in a predetermined condition, the second information processing devicepresents to the user that the transmitter, the receiver, or both of them are in the predetermined state.

400 100 200 300 100 Information on the arrangement of the transmitter 200 Information on the arrangement of the receiver Information on power consumption Information on power intensity Further, the second information processing apparatusanalyzes information relating to the state of the transmitterand the receiverstored in the first information processing apparatus, and presents predetermined information to the user. The predetermined information includes:

2 FIG. 1 FIG. 2 FIG. 100 200 100 200 100 200 100 200 200 100 200 200 100 is a block diagram showing an example configuration of the transmitterand the receivershown in. As shown in, the transmitterand the receiverare, for example, separated from each other by a predetermined interval. For example, the transmitterand the receiverare installed at a distance of about several meters apart. Specifically, for example, the transmitteris fixed and installed at a high position indoors, such as on a ceiling or a predetermined high position provided on a wall. The receiveris installed on a predetermined device indoors or placed near a device that requires power supply. The receivermay also be carried by a user. The transmittertransmits a power supply signal to the receiverusing a radio wave of a predetermined frequency, for example, in the 920 MHz band. The receiverconverts the power supply signal transmitted from the transmitterinto electric power, and either charges the converted power or supplies the converted power to a predetermined device.

100 101 102 103 104 105 101 103 104 The transmitterincludes, for example, an oscillator, a transmitting antenna, a microcontroller (controller), a data transceiver, and a data transmission/reception antenna. The oscillator, the microcontroller, and the data transceivermay be mounted on, for example, a PCB (printed circuit board).

101 The oscillatoroscillates a signal in a predetermined frequency band, for example, the 920 MHz band. The oscillated signal may be amplified and unnecessary frequency components may be removed, as necessary.

102 102 101 For example, the transmitting antennais formed to efficiently transmit radio waves in the 920 MHz band. The transmitting antennaradiates the signal oscillated by the oscillatoras a power supply signal.

103 100 103 103 102 The microcontrollercontrols the operation of the transmitter. The microcontrolleris realized, for example, by a semiconductor device equipped with an ARM processor. For example, the microcontrollercontrols transmission of radio waves by the transmitting antenna.

1 200 103 102 200 200 200 102 103 102 103 103 For example, in a WPT systemused in a factory, it is desirable for the receiverto supply power exceeding a predetermined value or more. Therefore, the microcontrollercontrols the transmission of radio waves by the transmitting antennabased on a feedback signal transmitted from the receiver. The feedback signal relates to, for example, a voltage value at a predetermined portion of the receiver. Based on the feedback signal, the electric field strength of the receivercan be pseudo-recognized. When the transmitting antennaincludes, for example, a plurality of antenna elements, the microcontrollercontrols the transmitting antennaso as to transmit the power supply signal from, for example, an optimal antenna element. For example, the microcontrolleradjusts the polarization direction of the power supply signal by switching the antenna elements to be driven. Further, the microcontrolleralso adjusts the driving timing of the antenna element to adjust the direction of the power supply signal.

1 103 102 200 102 103 102 Further, in a WPT systemused in a room such as a building, the microcontrollercontrols transmission of radio waves by the transmission antennabased on a feedback signal transmitted from the receiver. When the transmitting antennais, for example, a single antenna element, the microcontrolleroptimizes the power transmission output from the transmitting antenna.

104 104 105 104 105 103 The data transceiverperforms processing such as analog conversion of digital data and modulation of analog data. Further, the data transceiverperforms processing such as demodulation of a signal extracted from data signals received by the data transmitting/receiving antenna, digitization of demodulated analog data, and the like. For example, the data transceiverextracts a feedback signal from the data signal received by the data transmitting/receiving antenna, converts the feedback signal into digital data, and transmits the digital data to the microcontroller.

105 105 104 105 200 For example, the data transmitting/receiving antennais formed to efficiently transmit and receive radio waves in the 2.4 GHz band, for example. The data transmitting/receiving antennaemits the data signal supplied from the data transceiver. Further, the data transmitting/receiving antennareceives a data signal transmitted from the receiver.

200 201 202 203 204 205 206 207 202 203 204 205 206 The receiverincludes, for example, a receiving antenna, a rectifier circuit, a power management unit, a charging unit, a microcontroller, a data transceiver, and a data transmission/reception antenna. The rectifier circuit, the power manager, the charging unit, the microcontroller, and the data transceivermay be mounted on, for example, a PCB or a FPC (flexible printed circuit).

201 201 102 For example, the reception antennais formed to efficiently receive radio waves in the 920 MHz band. The receiving antennareceives the power supply signal radiated from the transmitting antenna.

202 The rectifier circuitrectifies a radio wave received as a power supply signal and converts the rectified radio wave into a DC voltage.

203 203 The power management unitmanages the DC voltage. For example, the power management unitcontrols a charging

203 204 203 204 voltage based on the DC voltage. The power management unitcharges the charging unitby controlling the charging voltage. In addition, the power management unitsupplies the DC voltage to a member to be connected, for example, when electric power of a predetermined capacity or more is stored in the charging unit.

203 204 205 In addition, the power management unitcauses the electric power stored in the charging unitto be discharged in response to control from the microcontroller.

204 203 204 203 204 The charging unitstores power in response to an instruction from the power management unit. In addition, the charging unitalso emits the stored power in response to an instruction from the power management unit. Details of the configuration of the charging unitwill be described later.

205 200 205 203 204 205 203 204 The microcontroller(hereinafter, sometimes referred to as an MCU (Microcontroller as appropriate) controls the operation of the receiver. The microcontrolleris driven by the DC voltage supplied from the power management unitor by power stored in the charging unit. The microcontrollercontrols the power management unitand causes the power stored in the charging unitto be discharged.

200 200 200 203 204 205 200 200 205 200 200 206 Various sensors are connectable to the receiver, for example. For example, a heat sensor, a temperature sensor, an optical sensor, a humidity sensor, a vibration sensor, etc. are connected to the receiver. A sensor connected to the receiveris driven by, for example, the DC voltage supplied from the power management unitor by power emitted from the charging unit. The microcontrollercontinuously or intermittently monitors a voltage value at a predetermined portion of the receiver, a status of a sensor connected to the receiver, information detected by the sensor, and the like. The microcontrollertransmits, as digital data, a voltage value at a predetermined portion of the receiver, the status of a sensor connected to the receiver, information detected by the sensor, and the like to the data transceiver.

206 205 206 206 203 204 The data transceiverperforms processing such as analog conversion of digital data supplied from the microcontrollerand modulation of analog data. Further, the data transceiverperforms processing such as demodulation of analog data, digitization of demodulated analog data, and the like. The data transceiveris driven by, for example, the DC voltage supplied from the power management unitor by power emitted from the charging unit.

207 207 206 207 100 207 203 204 For example, the data transmitting/receiving antennais formed so as to efficiently transmit and receive radio waves in the 2.4-GHz band. The data transmitting/receiving antennaemits a data signal supplied from the data transceiver. Further, the data transmitting/receiving antennareceives a data signal transmitted from the transmitter. For example, the data transmitting/receiving antennais driven by, for example, the DC voltage supplied from the power management unitor by power emitted from the charging unit.

207 207 104 100 200 300 The transmission format of the data signal transmitted (radiated) from the data transmitting/receiving antennais arbitrary. In particular, since the data signal radiated from the data transmitting/receiving antennais a radio wave in the 2.4 GHz band, it may be a signal conforming to the Bluetooth (registered trademark) or IEEE 802.11x (i.e., so-called wireless LAN) format. In this case, it is preferable that the data transceiverof the transmitteralso has a function of analyzing a data signal whose format matches the format of the data signal transmitted from the receiver. Alternatively, the first information processing apparatusmay have such a function.

3 FIG. 2 FIG. 2 FIG. 2 FIG. 200 200 200 is a diagram schematically showing a circuit configuration of the receivershown in. In the following description, detailed description of the constituent elements of the receiverdescribed with reference towill be omitted. In addition, only a main part of the components of the receivershown inis illustrated.

3 FIG. 204 200 204 204 204 204 204 204 204 204 a b a b a b a b 1 2 1 2 1 2 As shown in, the charging unitconstituting the receiverof the present embodiment has two capacitors(C),(C) connected in parallel. The capacitance C, Cof each capacitor,is selected so that the capacitance Cof the capacitoris equal to or smaller than the capacitance Cof the capacitor. Here, the capacitorcorresponds to “one capacitor” described above, and the capacitorcorresponds to “another capacitor” described above.

1 2 204 200 205 100 204 200 205 200 a b How to set the value of the capacitance Cof the capacitormay be determined by how quickly the receiveris to be brought in to an operable state, in other words, by how long the microcontrolleror the like can operate stably after starting power reception from the transmitter. In addition, how much the capacitance Cof the capacitoris set may be determined based on whether or not the stable operation of the receiver(mainly, the microcontrolleror the like) is to be ensured even if the power reception status of the receiverbecomes unstable.

1 2 204 204 204 204 204 204 204 204 a b b a a b As a method of setting the capacitance C, Cof the capacitors,, for example, a method in which the capacitoris constituted by an electric double-layer capacitor and the capacitoris constituted by a ceramic capacitor or the like is exemplified. The ceramic capacitor can be miniaturized and serves to optimize the board occupation area of the charging unit. On the other hand, an electric double-layer capacitor has a large capacity, and is preferably used to stabilize the power supply to a microcontroller or the like. Naturally, there is no particular limitation on the difference in capacity or the type of the capacitors,, and it may be determined as appropriate depending on what kind of operation is expected from the charging unit(that is, how much rapid charging and stability of power supply are expected).

204 204 204 205 204 204 204 204 204 c b d b c d b. The charging unitalso has a switchinterposed in a power supply path from the capacitorto the microcontroller, and a field-effect transistor (FET)interposed in the grounding-side path of the capacitor. These switchand the field-effect transistorconstitute a first current control unit that adjusts the supply current to the capacitor

100 204 203 204 204 203 204 205 205 c a c c 1 1 At the beginning of receiving power from the transmitter, the switchis in an OFF state. The power management unitmonitors an inter-terminal voltage Vof the capacitor, and when the inter-terminal voltage Vreaches a constant value (for example, 2V), the switchis turned ON by an instruction from the power management unit. The voltage at which the switchis turned ON need not be a voltage enough to stably operate the microcontroller, and may be a voltage at which the microcontrollercan start operating.

204 205 204 205 205 205 204 205 204 d b d d The gate terminal of the field-effect transistoris connected to the microcontroller, and controls the charging current supplied to the capacitorby a gate voltage supplied from the microcontroller. When the microcontrollerdoes not have a terminal capable of finely adjusting the voltage value of the gate voltage (for example, it does not have an analog output terminal), a voltage adjuster (not shown) may be provided between the microcontrollerand the field-effect transistor. The microcontrollermay send a command for analog control of the gate voltage of the field-effect transistorto the voltage adjuster, and the voltage adjuster may perform analog control of the gate voltage.

204 204 204 205 b d b In the present embodiment, the charging current supplied to the capacitoris controlled by the field-effect transistor, but the charge current supplied to the capacitormay be controlled by another device, for example, a bipolar transistor. In this case, the microcontrollermay control the base current of the bipolar transistor.

200 3 FIG. 4 FIG. Hereinafter, an example of the operation of the receiverof the present embodiment will be described with reference toand.

100 200 100 200 201 200 202 204 204 203 When the supply of the power feeding power from the transmitterto the receiveris started, in other words, when transmission of the wireless power supply signal, which is a substantially continuous continuous wave, from the transmittertoward the receiveris started, the receiving antennaof the receiverreceives the wireless power supply signal, the wireless power supply signal, which is a received AC signals, is converted into the DC voltage by the rectifier circuit, and a charging voltage for charging the charging unitis supplied to the charging unitby the power management unit.

204 204 203 204 204 204 203 204 204 204 c a a a b b b 4 FIG. 1 2 At this point, since the switchof the charging unitis still an OFF state, the output voltage from the power managing unitis supplied entirely to the capacitor, and only the capacitoris charged. As shown in, the inter-terminal voltage Vbetween the terminals of the capacitorincreases. On the other hand, since the output voltage from the power manageris not supplied to the capacitor, the capacitoris not charged, and the voltage Vbetween the terminals of the capacitorremains zero.

100 200 204 204 204 204 204 204 204 a a b a a c 1 2 As described above, immediately after the start of supply of power feeding power from the transmitterto the receiver, only one capacitoramong the capacitors,constituting the charging unitis charged. The capacitoris rapidly charged since the capacitance Cof the one capacitoris set to be equal to or smaller than the capacitance Cof another capacitor. This state is continued only for a period until the switchis turned ON (i.e., for a predetermined period of time).

204 100 204 100 205 a c Accordingly, since the capacitorcan be sufficiently charged in a short time, the time from the start of the wireless power supply from the transmitterto the turning-ON of the switchcan be kept short, and consequently, the time from the start of the wireless power supply from the transmitterto the start of the operation of the microcontrolleror the like can be shortened.

1 204 203 204 204 204 204 204 a c a b a b. Next, when the inter-terminal voltage Vbetween the terminals of the capacitorexceeds a predetermined value, the power managing unitturns ON the switch. As a result, the charging voltage is supplied to any of the capacitors,constituting the charging unit, and the charging is performed for any of the capacitors,

204 204 204 204 204 205 205 a b c a b 1 2 However, when the charge to any capacitors,is started by turning ON the switch, it is expected that the inter-terminal voltage Vand Vbetween terminals of the capacitorandtemporarily decrease, and the supply voltage to the microcontrollerfalls below a voltage at which the microcontrollercan continue operation.

204 205 204 204 204 204 c d d b b 3 4 FIG. Therefore, when the switchis turned ON and the supply of operating voltage is started, the microcontrollergradually increases a gate voltage Vof the field-effect transistoras shown inthereby gradually decreasing a resistance value of the field-effect transistor. As a result, the supply current to the capacitoris gradually increased, and the capacitoris gradually charged.

204 204 204 204 d d a b 3 4 FIGS.and 1 2 Thereafter, when the gate voltage of the field effect transistorrises to a certain value (1.8V in), the resistance value of the field effect transistorbecomes minimum, and a combined voltage value V+Vof the inter-terminal voltages of the capacitorandincreases.

204 204 100 100 200 200 204 205 204 a b b b Thus, since both of the capacitorandare sufficiently charged, even if the wireless power supply signal from the transmittertemporarily interrupted (for example, a person intervenes between the transmitterand the receiver) and the power supply state of the receiverdeteriorates, the capacitorhaving a large capacitance is sufficiently charged, so that the operation of the microcontrolleror the like can be continued by power supply from the capacitoruntil the power supply state is restored.

1 200 200 As described above, according to the WPT systemof the present embodiment, in the receiverthat is wireless powered, both the quick operation of the receiverand stable continuation of operation can be achieved.

1 204 100 204 204 1 c b a In the WPT systemof the first embodiment described above, by turning ON the switchafter a predetermined time has elapsed from the start of the wireless power supply from the transmitter, the supply of a charging voltage of the other capacitoris performed after a predetermined time, thereby rapidly charging the one capacitor. In the WPT systemaccording to the second embodiment, by making a current supplied to the other capacitor smaller than a current supplied to the one capacitor, the time until completion of charging of the one capacitor is made earlier than the time until completion of charging of the other capacitor.

5 FIG. 204 200 1 is a circuit diagram showing a configuration of the charging unitof the receiverin the WPT systemaccording to the second embodiment.

204 204 204 204 204 204 204 204 204 204 204 204 5 FIG. e f g e g e f g e f g 3 1 2 1 2 3 3 1 2 The charging unitaccording to the second embodiment shown inhas three capacitors(C),(C), and(C) connected in parallel. The capacitances C, C, Cof the respective capacitorstoare selected so that the capacitance Cof the capacitoris equal to or smaller than the capacitance Cof the capacitorand the capacitance Cof the capacitor. Here, the capacitorcorresponds to “one capacitor” described above, and the capacitors,correspond to the “other capacitors” described above.

1 2 3 1 2 1 2 1 2 3 204 204 204 204 204 204 204 204 204 e g f g e e g e. As a method of setting the capacitances C, C, Cof the capacitorsto, for example, similarly to the first embodiment, a method is mentioned in which the capacitorsandare constituted by electric double-layer capacitors and the capacitoris constituted by a ceramic capacitor or the like. In the charging unitof the present embodiment, the capacitance Cof the capacitorand the capacitance Cof the capacitorare set to be the same capacitance, but the capacitance C, Cmay be large or small. At least the capacitance C, Cmay be larger than the capacitance Cof the capacitor

204 204 204 204 h i e f. A Zener diodeand a resistorare interposed in parallel and in the charging power supply path for the capacitorsand

204 204 204 204 204 204 204 204 204 204 204 204 h h e f h f g i f g h c The Zener diodeis connected in a so-called reverse direction. That is, the cathode of the Zener diodeis connected to the side of the capacitor, and the anode is connected to the side of the capacitor. This Zener diodelimits the charging power supplied to the capacitorandto the path via the resistoruntil the charging voltage supplied to the capacitorandreaches a certain value, i.e., until it reaches the breakdown voltage. Therefore, the breakdown voltage of the Zener diodeis set to a voltage value (e.g., 2V) which is the condition under which the switchis turned ON in the case of the first embodiment, or to a value slightly below this voltage value.

204 204 204 204 204 204 204 204 204 100 i f g e f g i f g 1 The resistoris provided so that the charging current to the capacitorsandis made smaller than the charging current of the capacitoruntil the charging voltage supplied to the capacitor,reaches a certain value. Therefore, a resistance value Rof the resistanceis set from the viewpoint of how long the charging of the capacitorsandis to be completed from the start of wireless power supply from the transmitter.

204 204 204 204 204 204 204 h i f g e f g These Zener diodeand resistorconstitute a second current control unit and a current limiting element that makes a supply current to the capacitorsandsmaller than a supply current to the capacitoruntil the charging voltage supplied to the capacitorsandreaches a certain value.

204 204 100 204 204 204 204 h i f g e h. In the present embodiment, the Zener diodeand the resistorare used as the second current control unit and the current limiting element, but any circuit configuration may be used as long as, during a period of time from the start of receiving the transmitting power from the transmitteruntil a predetermined time, the charging current of the capacitorsandis made smaller than the charging current of the capacitor, and known configurations can be suitably applied. As an embodiment, a Schottky diode may be used instead of the Zener diode

200 5 FIG. Hereinafter, an example of the operation of the receiverof the present embodiment will be described with reference to.

100 203 204 204 203 204 204 204 204 204 204 204 204 204 204 e e e h f g i i e f g e. 1 Similarly to the case of the first embodiment, when wireless power supply from the transmitteris started, a DC voltage from the power managing unitis supplied to the capacitor, and charging of the capacitoris started. At this time, the DC voltage from the power manageris used as a charging voltage for the capacitor, and since the voltage applied to the Zener diodedoes not exceed the breakdown voltage, charging power is supplied to the capacitorsandonly via the resistor. The current value of this charging power is a current corresponding to the resistance value Rof the resistor, and is smaller than the current value of the charging power to the capacitor. Therefore, the charging of the capacitorsandproceeds more slowly than the charging of the capacitor

204 204 204 204 204 204 204 203 204 204 e h f g h i e f g. Thereafter, when the charging of the capacitorprogresses (that is, after a predetermined time has elapsed), the voltage applied to the Zener diodeexceeds the breakdown voltage, and charging power is supplied to the capacitorsandvia a path through the Zener diodetogether with a path through the resistor. Since by this time the charging of the capacitorhas already progressed considerably, the charging power supplied from the power managing unitis mainly used for charging the capacitorsand

204 100 204 100 205 e h Accordingly, since the capacitorcan be sufficiently charged in a short time, the time from the start of wireless power supply from the transmitteruntil the voltage applied to the Zener diodeexceeds the breakdown voltage can be kept short, and consequently, the time from the start of wireless power supply from the transmitteruntil the start of operation of the microcontrolleror the like can be shortened.

204 204 204 100 100 200 200 204 204 205 204 204 204 204 204 204 204 204 204 204 204 h e g f g f g h f g i f g h f g Further, when the voltage to the Zener diodeexceeds the breakdown voltage, since the charging power is supplied to all of the capacitorsto, even if the wireless power supply signal from the transmitteris temporarily interrupted (for example, a person intervenes between the transmitterand the receiver) and the power supply state of the receiverdeteriorates, the capacitorandhaving large capacitance is sufficiently charged; therefore, the operation of the microcontrolleror the like can be continued by the power supply from the capacitorsand, until the power supply state is restored. Moreover, even at a time when the voltage applied to the Zener diodedoes not exceed the breakdown voltage, charging power is supplied to the capacitorsandvia the resistor, so the capacitorsandcan be charged even at a time when the voltage applied to the Zener diodedoes not exceed the breakdown voltage, and consequently, the time until the capacitorsandis sufficiently charged can be shortened.

1 1 200 200 As described above, according to the WPT systemof the present embodiment, similarly to the WPT systemof the first embodiment, in the receiverthat is wirelessly powered, both quick operation of the receiverand stable continuation of operation can be achieved.

It should be noted that the embodiments described above have described the configuration in detail to explain the present disclosure in an easy-to-understand manner and are not necessarily limited to those having all of the configurations described. Further, some of the configuration of each embodiment may be added to, deleted from, or replaced with other configurations.

In addition, each of the above configurations, functions, processing units, processing means, and the like may be implemented in hardware, for example, by designing some or all of them as an integrated circuit. The present invention can also be realized by program code of software that realizes the functions of the embodiments. In this case, a storage medium in which the program code is recorded is provided to the computer, and the processor included in the computer reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the program code itself and the storage medium storing the program code itself constitute the present invention. As a storage medium for supplying such a program code, for example, a flexible disk, a CD-ROM, DVD-ROM, a hard disk, a SSD, an optical disk, a magneto-optical disk, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used.

In addition, the program code that realizes the functions of the embodiment can be implemented in a wide range of programs or script languages such as an assembler, C/C++, Perl, Shell, PHP, and Java (registered trademark), and the like.

Further, the program code of the software for realizing the functions of the embodiment may be distributed via a network and stored in a storage means such as a hard disk or a memory of a computer or a storage medium such as a CD-RW, CD-R, and the processor included in the computer may read and execute the program code stored in the storage means or the storage medium.

It should be noted that the configuration of the present disclosure may also be employed for the purpose of impedance matching. Specifically, impedance matching is generally performed by disposing a matching circuit between an antenna and a rectifier circuit and adjusting the circuit so as to conform to a load impedance as seen by the rectifier circuit. Here, when attempting to implement an auto-matching function on an integrated circuit, because forming an inductor element is difficult, because forming an inductance on an IC involves issues of size limitation and power loss, the matching circuit has to be configured using only capacitors, and as a result, there is a constraint that the adjustable impedance-matching range becomes limited. In addition, sensors, communication modules, and the like are connected to a subsequent stage of the rectifier circuit, and because the load impedance varies according to their operating states, even if impedance matching is optimized only in a preceding stage, the matching accuracy degrades due to variations on the load side.

In contrast, by adopting the configuration of the present disclosure, auto-matching control within a limited range using capacitors can be performed in a preceding stage (between the antenna and the rectifier circuit), while combinations of multiple capacitors can be controlled in a subsequent stage (downstream of the rectifier circuit) to smooth out variations in load impedance. Specifically, at the initial stage of power reception, because the control unit is not yet operating, reception is performed using one capacitor; after the control unit starts up, other capacitors are additionally controlled as a matching network, thereby realizing dynamic impedance matching. A “matching network” refers to a network (circuit) inserted in a wireless circuit or a wireless power-transfer circuit to match circuit impedance. More specifically, the matching network is a circuit network disposed between the antenna and the rectifier circuit, or in a subsequent stage of the rectifier circuit, which adjusts input impedance by combining multiple capacitors. In this way, a limitation of adjustment only in the preceding stage can be compensated by capacitor control performed in the subsequent stage, and matching accuracy as a whole is improved by approaches from both the preceding and subsequent stages. Such a capacitor control function may be configured as a matching unit disposed between the antenna and the rectifier circuit, or in a subsequent stage of the rectifier circuit.

That is, when interpreting the present embodiment as applied to impedance matching, the power management unit may manage a rectified DC voltage obtained by rectifying an input AC signal, similar to a simple clipping circuit such as a Zener diode. The charging unit is not necessarily limited to the purpose of storing electric charge, and may be used as a capacitor array that adjusts input impedance by combining multiple capacitors. Furthermore, the control unit may include an LDO (Low Dropout Regulator), an energy-storage element, a microcontroller, and the like, and may control, via these elements, the connection states of capacitors in the matching unit and the supply current.

In this case, at the initial stage of receiving transmitting power, because the control unit is inactive, reception is performed using one capacitor to realize basic impedance matching. After the control unit starts up, other capacitors are additionally connected as the matching network, thereby compensating not only the impedance in the preceding stage but also variations in load impedance in the subsequent stage, and realizing dynamic and high-precision impedance matching.

As described above, a receiver configured for the purpose of impedance matching may be connected to the rectifier circuit or the power management unit and may include a matching unit having multiple capacitors that adjust input impedance. The matching unit can perform impedance matching in a signal path from the antenna to the rectifier circuit by switching the connection states of multiple capacitors or by controlling the supply current.

Furthermore, the matching unit may be connected between the antenna and the rectifier circuit and, by switching combinations of multiple capacitors, may realize impedance matching in the preceding stage. According to this configuration, matching adjustment on an antenna-input side can be performed using only capacitor arrays that can be formed within an IC, thereby avoiding the difficulty of forming inductor elements while providing a compact matching function.

Moreover, the control unit may monitor an operating state of a load connected to a subsequent stage of the rectifier circuit, such as a sensor module or a communication module, and dynamically control the connection states of multiple capacitors of the matching unit according to the load. According to this configuration, impedance variations caused by load operation can be smoothed out, a decrease in matching accuracy in the preceding stage can be prevented, and impedance matching can be optimized from both the preceding and subsequent stages.

Accordingly, in the receiver according to the present disclosure, basic matching is performed using one capacitor at the initial stage of power reception, and after the control unit is activated, other capacitors are additionally connected to form a matching network, whereby variations in load impedance are suppressed and high-precision impedance matching can be maintained as a whole.

In the receiver of the present disclosure, by identifying an optimal input impedance at which the rectifier circuit exhibits maximum rectification efficiency and by controlling the matching unit to adjust to the optimal value, high rectification efficiency can be maintained even during load variations. Specifically, the connection states of the capacitor array are controlled such that the ratio between the input impedance of the rectifier circuit and the radiation resistance Rrad of the antenna (Rrad/Rload) falls within a predetermined range.

As a method for identifying the optimal input impedance, source-pull testing can be employed. In source-pull testing, a variable impedance circuit is connected to the front stage of the rectifier circuit, and the impedance of the power supply source is systematically varied while measuring the rectification efficiency (rectified DC output power/input RF power) at each impedance value. From the measurement results, the impedance value at which the rectification efficiency is maximized (optimal source impedance Zopt) is identified, and this value is used as a target value for controlling the matching unit.

For example, the rectification efficiency at multiple impedance points on a Smith chart is measured to identify the region where efficiency is maximized. For the identified optimal impedance Zopt (e.g., 30+j20Ω), the matching unit adjusts the input impedance as seen from the antenna to approach Zopt by combining multiple capacitors. This adjustment enables the rectifier circuit to always operate near its maximum efficiency point.

Furthermore, when the optimal impedance varies according to the load state (sensor operation, communication module transmission, etc.), optimal impedance values corresponding to multiple operation modes can be stored as a lookup table in the memory of the control unit, and an appropriate target impedance can be selected based on the detected load state. This suppresses degradation of rectification efficiency even against dynamic load variations.

As another embodiment of the present disclosure, by widening the frequency characteristics of impedance matching to achieve broadband operation, robustness against receiving frequency variations and impedance changes due to load variations can be improved. Conventionally, narrowband matching circuits with high Q-factors (Quality Factors) have suffered from the problem that the matching state significantly degrades with slight frequency deviations or load variations.

As a first approach to broadband design, a configuration in which a matching circuit is disposed on the rectifier circuit side (diode side) to reduce the overall Q-factor of the circuit can be adopted. Specifically, by intentionally inserting a series resistance component on the input side of the rectifying diode or by providing multiple parallel paths, the frequency dependence of the impedance characteristics is mitigated. This expands the bandwidth of the matching circuit, making it possible to maintain a VSWR of 2.0 or less within a range of ±X MHz (e.g., ±5 MHz) from the center frequency.

As a second approach to broadband design, a hierarchical broadband design method can be adopted in which both the front-stage matching unit (between antenna and rectifier circuit) and the rear-stage matching unit (downstream of rectifier circuit) are respectively responsible for different frequency bands. For example, the front stage performs narrowband matching centered on the center frequency f0, while the rear stage compensates for equivalent frequency deviations (changes in impedance locus) caused by load variations. This two-stage approach achieves broadband and high-efficiency operation that is difficult to achieve with a single-stage matching circuit.

Additionally, the control unit can monitor the frequency of the received signal and, when frequency deviation is detected, dynamically switch to the optimal capacitor combination for that frequency. This enables maintaining a good matching state even against frequency variations on the transmission side or frequency shifts due to the Doppler effect.

As a further embodiment of the present disclosure, when the load circuit (sensor, communication module, etc.) does not require continuous operation, optimization of power supply in the time domain can be performed. Specifically, received power is temporarily accumulated in a capacitor (energy storage unit), and duty cycle control is implemented to drive the load circuit intermittently.

(1) Charge the storage capacitor with received power (charging time: e.g., 900 ms) (2) Detect that the voltage of the storage capacitor has reached a threshold Vth (e.g., 3.0V) (3) Supply power to the load circuit (sensor) and execute measurement operation (operation time: e.g., 100 ms) (4) After measurement completion, return to the charging phaseThis intermittent driving method enables securing the necessary power at peak times even when the average received power is low. Furthermore, since the optimal matching conditions differ between the charging phase and discharging phase, the control unit dynamically switches the connection state of the capacitor array according to each phase, thereby maximizing power transfer efficiency in each phase. For example, if a sensor requires only one measurement per second, there is no need to supply power continuously, and it is sufficient to meet the instantaneous high power demand during measurement. For such applications, the control unit performs the following operations:

Moreover, by adjusting the duty cycle (load operation time/total cycle time), the trade-off between average power consumption and response speed can be optimized. For example, when fast response is required, the duty cycle is set to 50%, and when low power consumption is prioritized, it is set to 10% or less. The control unit comprehensively evaluates the voltage level of the storage capacitor, the intensity of received power, and the operational requirements of the load, and dynamically determines an appropriate duty cycle.

To optimize the performance of the receiver according to the present disclosure, it is important to separately evaluate the individual performance of each element constituting the overall system (antenna, matching circuit, rectifier circuit, load circuit) and the overall performance resulting from their combination.

11 (1) Measurement of antenna radiation efficiency alone: Measure the reflection coefficient (S) and radiation pattern at the antenna port to quantify losses in the antenna itself 11 (2) Measurement of matching loss between antenna and matching circuit: Measure Safter connecting the matching circuit to evaluate additional losses caused by the matching circuit (3) Measurement of rectifier circuit conversion efficiency: Supply known input power from a standard signal source and measure rectified DC output power to evaluate the efficiency of the rectifier circuit alone (4) Measurement of end-to-end efficiency of the entire system: Receive from an actual transmitting antenna and measure the overall efficiency up to the final load circuit As an example of an evaluation method, the following stepwise measurements are performed:

By comparing these measurement results, it is possible to quantitatively isolate whether the cause of efficiency degradation in the overall system lies in antenna-side issues (radiation efficiency, poor matching) or in issues downstream of the rectifier circuit (rectification loss, load variations).

Furthermore, the control unit can automatically select the most effective improvement measure based on these evaluation results. For example, if losses between the antenna and matching circuit are dominant, priority is given to adjusting the front-stage capacitor array; if losses downstream of the rectifier circuit are dominant, priority is given to rear-stage control or intermittent driving control. Such adaptive control achieves optimal power transfer according to operating environment and load conditions.

Additionally, by monitoring the difference between the theoretically maximum efficiency predicted by simulation and the measured efficiency, performance degradation due to aging or environmental changes can be detected early and utilized as a self-diagnosis function. When the efficiency degradation falls below a predetermined threshold (e.g., 80% or less of the theoretical value), the control unit can output a warning signal or transition to an alternative operation mode.

The present invention relates to an optimization control technique for rectification efficiency and impedance matching characteristics in a wireless power transfer system. More particularly, the invention concerns a control method capable of realizing a wide range of matching states by making a capacitor configuration variable and automatically selecting an optimal configuration in response to environmental changes and load fluctuations. Conventionally, in wireless power transfer systems, variations in coupling conditions between transmitting and receiving units or in load conditions tend to cause mismatching and deterioration of rectification efficiency. In contrast, configurations employing fixed-value matching or rectifying circuits restrict the operating point, making it difficult to maintain high efficiency. The present invention achieves optimal impedance matching and rectification efficiency by generating a plurality of effective capacitances through a combination of multiple capacitors formed on an integrated circuit (IC), connected in series or in parallel by switching elements, and dynamically controlling these combinations. In addition, two independent control loops are provided—one on the RF input side and the other on the rectified load side—each operating to maximize reflected power loss suppression and output power, respectively.

In one embodiment, the configuration of the impedance matching section between the antenna and the rectifier employs variable capacitors. The use of capacitors for this purpose is as described above. In the present invention, the capacitance range of MOS capacitors formed on the IC is approximately 0.1 pF to several tens of pF. For example, by preparing three types of capacitors having capacitances of 1 pF, 2 pF, and 4 pF, and connecting them in series or parallel via switches, eight different effective capacitance values (approximately 0.57 pF to 7 pF) can be obtained from the three elements. Furthermore, by providing two such capacitor blocks and connecting them in series or parallel, up to 128 combinations can be generated. When similar configurations are provided on the load side, 128 combinations exist on both the transmitting and receiving sides, resulting in a total of 128×128=16,384 possible configurations.

6 FIG. 6 FIG. 6 FIG. Next, the control method will be described. In the present invention, a two-stage loop control configuration is employed. A timing chart illustrating this control scheme is shown in the.is a diagram illustrating an example of a timing chart when the present disclosure is applied to impedance matching. As shown in, in a first control loop (RF-side matching control), a switchable L-, π-, or T-type matching network is used to select, from among the 128 capacitance combinations, the configuration that minimizes reflection loss (|Γ|). This optimizes the impedance matching between the antenna and the rectifier. In a second control loop (post-rectification load control), the rectified output voltage or output power is monitored, and the load side is controlled to maximize that output. Such control may be performed by adjusting the gate bias of an active rectifier, switching the number of rectifying stages, or altering the configuration of a capacitor relay circuit. That is, the RF loop optimizes input matching, while the DC-side loop performs dynamic control to achieve maximum rectification efficiency of the received power. These two loops are alternately or time-multiplexedly executed to maintain stable and highly efficient overall system operation.

7 FIG. 7 FIG. Finally, a circuit configuration according to one embodiment of the invention will be described.is a diagram illustrating an example of a circuit configuration when the present disclosure is applied to impedance matching. As shown in, in this embodiment, an RF signal is input to a variable matching network via an antenna. The matching network is switched under control of the aforementioned switching circuit, and a DC output is obtained after rectification. A capacitor relay circuit is connected to the output side of the rectifier, and by selectively switching among multiple capacitor groups, the power conversion efficiency is optimized according to load conditions. Overall control of these operations is performed by a microcontroller (MCU) or dedicated logic circuitry, which coordinates the timing between RF matching control and load control. According to the present invention, even when external environmental conditions or load characteristics change, optimal impedance matching and rectification conditions can be automatically maintained, thereby significantly improving the overall power transfer efficiency of the wireless power transfer system compared to the prior art. Furthermore, in order to prevent unnecessary power consumption caused by MCU control operations, a portion or all of the control functions may be separated from the MCU and implemented using analog circuitry, such as comparators or logic gates, configured to operate with ultra-low power consumption.

The matters described in the respective embodiments above are appended below.

200 200 202 203 202 204 203 204 200 204 204 204 204 204 204 a b a b a A receiver () that wirelessly receives transmitting power composed of AC signals, the receiver () comprising: a rectifier () that rectifies the transmitting power; a power management unit () that manages a rectified voltage from the rectifier (); a charging unit () that is charged with an output voltage from the power management unit (); and a control unit that operates on a power supplied from the charging unit () and controls the entire receiver (), wherein the charging unit () includes a plurality of capacitors (,), and performs charging of one of the plurality of capacitors () from the start of receiving the transmitting power until a predetermined time, and also charges another capacitor () other than the one capacitor () after the predetermined time.

204 204 a b The receiver according to Appendix 1, wherein a capacitance of the one capacitor () is equal to or smaller than a capacitance of the other capacitor ().

200 204 204 204 204 204 204 204 204 204 c d b c d b a b The receiver () according to Appendix 2, wherein the charging unit () has a first current control unit (,) that adjusts a supply current to the other capacitor (), and the first current control unit (,), by adjusting the supply current to the other capacitor (), performs charging of the capacitor () from the start of receiving the transmitting power until a predetermined time, and performs charging of the other capacitor () after a predetermined time.

200 204 204 204 204 204 c d d b d The receiver () according to Appendix 3, wherein the first current control unit (,) is a field-effect transistor (), and controls the supply current to the other capacitor () by controlling a current between a source and a drain of the field-effect transistor ().

200 205 204 204 d d The receiver () according to Appendix 4, wherein the control unit () controls the current between the source and the drain of the field-effect transistor () by controlling a gate voltage of the field-effect transistor ().

200 205 204 204 b d The receiver () according to Appendix 5, wherein the control unit () monitors a charging voltage to the other capacitor () and controls the current between the source and the drain of the field-effect transistor () based on the charging voltage.

200 200 202 203 202 204 203 205 204 200 204 204 204 204 204 204 204 204 204 204 204 e g h i f g e g e A receiver () that wirelessly receives transmitting power composed of AC signals, the receiver () comprising: a rectifier () that rectifies the transmitting power; a power managing unit () that manages a rectified voltage from the rectifier (); a charging unit () that is charged with an output voltage from the power managing unit (); and a control unit () that operates on power supplied from the charging unit () and controls the entire receiver (), wherein the charging unit () includes a plurality of capacitors (to), and the charging unit () includes a second current control unit (,) that, during a period from the start of receiving the transmitting power until a predetermined time, makes a charging current of other capacitors (,) among the plurality of capacitors (to) less than a charging current of one capacitor ().

200 204 204 204 204 204 204 204 204 204 h i h i e f g e g The receiver () according to Appendix 7, wherein the second current control unit (,) is a current limiting device (,) interposed between the one capacitor () and the other capacitor (,) in a charging power supply path for the plurality of capacitors (to).

200 204 204 204 e f g The receiver () according to Appendix 8, wherein a capacitance of one capacitor () is equal to or smaller than capacitances of the other capacitor (,).

1 100 200 200 202 203 202 204 203 204 200 204 204 204 204 204 204 a b a b a A wireless power supply system () comprising a transmitter () that wirelessly transmits transmitting power composed of AC signals, and a receiver () that wirelessly receives the transmitting power, the receiver () comprising: a rectifier () that rectifies the transmitting power; a power management unit () that manages a rectified voltage from a rectifier (); a charging unit () that is charged with an output voltage from the power management unit (); and a control unit that operates on a power supplied from the charging unit () and controls the entire receiver (), wherein the charging unit () includes a plurality of capacitors (,), performs charging of one of the plurality of capacitors () from the start of receiving the transmitting power until a predetermined time, and also charges another capacitor () other than the one capacitor () after the predetermined period of time.

1 100 200 200 202 203 202 204 203 205 204 200 204 204 204 204 204 204 204 204 204 204 204 e g h i f g e g e A wireless power supply system () comprising a transmitter () that wirelessly transmits transmitting power composed of AC signals, and a receiver () that wirelessly receives the transmitting power, the receiver () comprising: a rectifier () that rectifies the transmitting power; a power management unit () that manages a rectified voltage from the rectifier (); a charging unit () that is charged with an output voltage from the power management unit (); and a control unit () that operates on power supplied from the charging unit () and controls the entire receiver (), wherein the charging unit () includes a plurality of capacitors (to), and the charging unit () includes a second current control unit (,) that, during a period from the start of receiving the transmitting power until a predetermined time, makes a charging current of the other capacitors (,) among the plurality of capacitors (to) smaller than a charging current of one capacitor ().

200 205 204 204 204 204 b a b a The receiver () according to any one of Appendices 1 to 11, wherein the control unit () suppresses charging of the other capacitor () until a terminal voltage of the one capacitor () reaches a predetermined threshold voltage, and permits charging of the other capacitor () after the terminal voltage of the one capacitor () reaches the threshold voltage.

200 205 200 204 204 a b The receiver () according to any one of Appendices 1 to 12, wherein the control unit () maintains operation of the receiver () when a supply of transmitting power is temporarily interrupted, by using a total capacitance of the plurality of capacitors (,).

200 100 The receiver () according to any one of Appendices 1 to 13, wherein the transmitting power transmitted from the transmitter () is a continuous wave.

200 200 202 203 202 206 202 203 206 206 206 205 206 206 206 205 206 205 206 206 202 202 201 a b a b a b a A receiver () that wirelessly receives transmitting power composed of AC signals, the receiver () comprising: a rectifying unit () that rectifies a received AC signal; a power management unit () that manages a rectified voltage from the rectifying unit (); a matching unit () connected to the rectifying unit () or the power management unit (), the matching unit () including a plurality of capacitors (,) for adjusting an input impedance; and a control unit () that controls a connection state or a supply current of the capacitors (,) of the matching unit (), wherein, at an initial stage of receiving the transmitting power, the control unit () performs impedance matching by using one of the capacitors (), and after activation of the control unit (), additionally connects another capacitor () other than the one capacitor () as a matching network, thereby equalizing fluctuations of an impedance at a subsequent stage of the rectifying unit () and maintaining impedance matching between the rectifying unit () and an antenna ().

200 206 201 202 202 206 206 a b The receiver () according to Appendix 15, wherein the matching unit () is connected between the antenna () and the rectifying unit (), and performs impedance matching at a preceding stage of the rectifying unit () by combining the plurality of capacitors (,).

200 205 206 206 207 202 a b The receiver () according to any one of Appendices 15, wherein the control unit () controls a connection state of the plurality of capacitors (,) according to an operating state of a load () connected to a subsequent stage of the rectifying unit (), thereby equalizing fluctuations of an impedance on a load side.

1 100 200 201 202 203 204 204 204 204 204 204 204 204 204 204 205 206 207 300 400 a b c f g c d h i . . . . WPT system. . . transmitter. . . receiver. . . receiver antenna. . . rectifier circuit. . . power manager. . . charging unit..... . . capacitor. . . switch. . . field-effect transistor. . . . Zener diode. . . resistor. . . microcontroller. . . data transceiver. . . data transceiver antenna. . . first information processing device. . . second information processing device